ANDROID: mm: madvise: vendor hook to tune page flags

Users can proactively reclaim the pages of an app once it is in
background using the system calls, like madvise.  But it may be possible
that such pages turn out to be the workingset page in the conventional
LRU which while swapping can result into accounting of PSI events.

Although this PSI events is an indication that wrong pages are being
madvised, one can also argue that he is aware of what he is doing using
madvise.

For such clients, add the vendor hook to tune page flags, such as
clearing the Workingset during swapout so that PSI might not get
accounyted during swapin.

Bug: 350429581
Change-Id: I675c57f63a918c5a23df8273006426d0e611c5c5
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>